%I #3 Oct 03 2021 15:32:15
%S 16,26,36,76,126,176,276
%N Numbers k such that there is regular 2-graph on k points with smallest eigenvalue rho_2 = -5.
%D Taylor, Donald E. "Regular 2-graphs." Proceedings of the London Mathematical Society 3.2 (1977): 257-274. See Theorem 3.8 and Table 2.
%K nonn,fini,full
%O 1,1
%A _N. J. A. Sloane_, Oct 03 2021